Huge thanks to everyone who took part in the poll and shared it on social media. In January, our small group of research-oriented ME/CFS patients including Simon McGrath, Graham McPhee, Carly Maryhew and others, asked our fellow ME/CFS patients to complete an important poll. The poll related to how the NIH/CDC were intending to measure post-exertional malaise (PEM) in all their future funded research. Patients were asked to say whether either or both of two lists of items broadly represented their own experience of PEM. One list consisted of the core PEM items from the PEM subscale of the DePaul Symptom Questionnaire, which the NIH/CDC propose to use to determine who is a PEM ‘case’. The other consisted of items derived from a description of PEM from the former Institute of Medicine (IOM), which the NIH/CDC adopted as their definition of PEM but which differs markedly from the DePaul list. Findings 783 patients responded in the five days that the poll was open. The results are shown in the graph below. Only 32% of patients said that the DePaul items broadly reflected their experience of PEM, compared to 92% who said that the IOM list did. Two questions in the poll asked what the NIH/CDC should do. In response to the question, ‘Should the working group make a strong recommendation to urgently develop a better questionnaire to assess PEM?’ 74% replied, ‘Essential’, 23% ‘Preferable’, and 3% ‘Unimportant’. In response to the question, ‘Is it acceptable to use the DePaul questionnaire (supplemented by [an informal researcher-assessment]) until a new PEM assessment tool is developed and tested?’ 52% replied ‘No’ (95% confidence interval 48% to 56%)’, 29% ‘Not sure’ and 19% ‘Yes’. The full results, with graphs, are in the atttached PDF file Comments It was impossible to avoid some bias in the poll because we had to explain to patients why they should take part (because there were doubts over the NIH/CDC’s planned approach). Also, many early respondents may have read comments critical of the DePaul items on an online forum that advertised the poll early on (but even amongst the latest responders, only 39% endorsed the DePaul list compared with 89% for the IOM). And the IOM items were not a list of questionnaire items like the DePaul list, so like was not being compared with like. But the poll had strengths in being very large and having been very widely circulated on social media, thus probably reaching a much wider and possibly more representative group than researchers or clinicians often do. The sheer size of the difference in the proportion of patients broadly recognising their own experience of PEM in the IOM rather than the DePaul items indicates to us that there would be problems in using the DePaul PEM subscale to determine whether a patient has PEM. Nearly all of the patients polled urgently want another PEM questionnaire to be developed. Around half think the core DePaul PEM subscale unacceptable to use in the interim and less than a fifth positively regard it as acceptable as an interim measure. This indicates serious problems with the DSQ PEM scale, from the point of view of patients. We believe that overall, the poll strongly supports the idea that we need a new, standalone questionnaire that can be demonstrated to measure what patients recognise as post-exertional malaise. Professor Leonard Jason But none of this should be read as criticism of the DePaul scale’s originator, Professor Leonard Jason, nor of the scale. The five core items on DePaul PEM subscale that the NIH/CDC propose to use were never designed to be used as a standalone questionnaire to determine whether a patient has PEM. They are part of a scale of about 100 items and were designed to screen for PEM, used along with other symptom ratings, as part of a process, including a medical exam, to determine whether a person has ME. Professor Jason’s work with the scale, and on ME case ascertainment in general, has much advanced the field. Patients owe him a great debt of gratitude for that work. Our only concern is with the NIH/CDC’s proposed use of the PEM subscale for a purpose for which it was never intended. A report concerning the results of the poll and other issues relating to assessing PEM has been submitted to the NIH/CDC. We would like to thank all the patients who took part in the poll and Professor Jason for engaging with us in the issues.